1. Field of the Invention
The present invention relates to a parking lock device for a three-wheeled vehicle suitable for lowering manufacturing costs and maintenance costs.
2. Description of the Background Art
A parking lock device for an oscillating type three-wheeled vehicle is disclosed in Japanese Patent Publication No. 1989-23356. The three-wheeled vehicle includes one front wheel mounted on the front body, and two wheels mounted on the rear body. The front body and the rear body are joined to be rolled freely by a joint part. The rear body is provided with a rear-wheel lock mechanism for locking the rear wheel by a brake or the like, whereby at the time of parking, rolling movement of the front body and the rear body is locked to lock (brake) the rear wheels.
A description will be made with reference to FIGS. 15 and 16 which correspond to FIGS. 1 and 2 of the aforementioned Patent Publication. FIG. 15 shows the main parts in the original FIG. 1. Reference numerals used indicate those used in the aforementioned Patent Publication.
FIG. 15 is a side view of main parts of a conventional three-wheeled vehicle. An oscillating type three-wheeled vehicle 200 is a vehicle in which a front body 201 on the front wheel side and a rear body 202 on the rear wheel side constitute a vehicle body. An oscillating joint 203 is mounted vertically movably by means of a pin 201a at the rear of the front body 201. A rear frame 204 is mounted at the rear of the oscillating joint 203. A rear wheel 205 and a brake arm 206 of a brake for braking the rear wheel 205 are arranged on the rear frame 204 side. A lock operating lever (not shown) for carrying out the parking lock is provided in the vicinity of a handle of the front body 201. A single operating cable 207 is connected to the oscillating joint 203 and the brake arm 206 from the lock operating lever.
FIG. 16 is a sectional view of a conventional oscillating joint, in which a support shaft 211 is rotatably mounted on a lower case 208 and an upper case (not shown) of the oscillating joint 203. A stopper plate 212 is mounted on the front end of the support shaft 211. A stopper pole 213 and a swing arm 214 are mounted in a manner free to swing on a lower case 208 for locking the rotation of the stopper plate 212. An inner (wire) 215 of the operating cable 207 is connected to the end of the swing arm 214, and the outer tube side of the operating cable 207 is divided into an outer 216 and an outer 217 with respect to the single inner (wire) 215.
7In the art of the aforementioned Patent Publication, mounting locations of the operating cable 207 on the body are a point 218 on the oscillating joint 203 and a point 219 in the vicinity of the brake arm 206. Since the points 218 and 219 are subjected to relative rolling movement by the oscillating joint 203, the operating cable 207 is twisted in a short distance (distance DA) between the points 218 and 219 to impose a burden to the operating cable 207. Accordingly, it is contemplated that in a case where miniaturization of the body is studied, if the dimension of the oscillating joint 203 is simply reduced, the twisting of the operating cable 207 becomes further increased, resulting in a shorter life of the operating cable 207, which poses restriction when miniaturization is taken into consideration.
Further, in FIG. 16, since the operating joint 207 has its midpoint connected to the oscillating joint 203, a plurality of parts are mounted in order that the outer tube side is divided (into the outer 216 and the outer 217), and the swing arm 214 is connected to the inner wire 215, which makes the construction of the operating cable 207 complicated, bringing forth an increase in manufacturing costs, and requiring many steps for the maintenance for mounting and dismounting or replacement of the operating cable 207.
It is therefore an object of the present invention, in a parking lock device for a three-wheeled vehicle, to miniaturize the body without receiving great restriction to reduce the weight, and to simplify the construction to lower part costs and maintenance costs.
For achieving the aforesaid object, the present invention provides a parking lock device for a three-wheeled vehicle in which a front body having a front wheel mounted thereon and a rear body having rear wheels mounted thereon are joined by a substantially laterally extending shaft and a bearing to thereby connect the front body and the rear body to be relatively rollable. By drawing a cable at the time of parking, the relative rolling between the front body and the rear body can be locked, and the rotation of the rear wheels can be locked. The front body is provided with a parking lever for drawing said cable. The rear body is provided with a rear-wheel lock mechanism for locking the rear wheels. A joint part between said shaft and said bearing is provided with a roll lock mechanism for locking the relative rotation between said shaft and said bearing. A front half part of the cable is extended over between said parking lever and said rear-wheel lock mechanism, and a rear half part of the cable is extended over between said rear-wheel lock mechanism and said roll lock mechanism.
Since the front half part of the cable is extended over between the front body and the rear body, the twisting of the cable caused by the relative rolling between the front body and the rear body is absorbed in a long distance as compared with the prior art. Thereby, even if the joint part is miniaturized, the excessive load is not applied to the cable to enable extension of the service life of the cable.
According to the present invention, the front half part of said cable is constituted by a first cable, and the rear half part of said cable is constituted by a second cable separate from the first cable. The first cable and the second cable can be made simple in construction. For example, if general cables are used, parts costs can be reduced considerably. Further, maintenance costs of cables can be lowered.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.